CN117124732A

CN117124732A - Liquid ejecting head, liquid ejecting apparatus, and piezoelectric device

Info

Publication number: CN117124732A
Application number: CN202310582136.7A
Authority: CN
Inventors: 古池晴信; 青木崇
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2022-05-25
Filing date: 2023-05-22
Publication date: 2023-11-28
Also published as: US20230382113A1; JP2023173338A

Abstract

The invention provides a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric device capable of maintaining reliability of a vibration plate at a wrist portion of the vibration plate and suppressing reduction of vibration efficiency. The vibration plate includes: a first layer containing silicon as a constituent element; a second layer containing a metal element other than zirconium as a constituent element; and a third layer including zirconium as a constituent element, wherein the active region is a region of the diaphragm that overlaps the pressure chamber when viewed in the first direction and overlaps the first electrode, the piezoelectric layer, and the second electrode, and the passive region is a region of the diaphragm that overlaps the pressure chamber when viewed in the first direction and does not overlap the first electrode, the piezoelectric layer, and the second electrode, and the diaphragm has the first layer, the second layer, and the third layer in the active region and the first layer and the second layer in at least a part of the passive region and does not have the third layer.

Description

Liquid ejecting head, liquid ejecting apparatus, and piezoelectric device

Technical Field

The present invention relates to a liquid ejecting head including a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode, a diaphragm that vibrates by driving of the piezoelectric element, and a pressure chamber substrate that divides a pressure chamber that applies pressure to liquid by vibration of the diaphragm, and a liquid ejecting apparatus including the piezoelectric element and the diaphragm.

Background

As a liquid ejection head which is one of electronic devices, an inkjet recording head is known. An inkjet recording head is provided with: a pressure chamber substrate provided with a pressure chamber communicating with the nozzle; a diaphragm provided on one surface side of the pressure chamber substrate; and a piezoelectric element provided on the vibration plate, wherein the ink in the pressure chamber is pressure-changed by driving the piezoelectric element, and ink droplets are ejected from the nozzles.

Here, various structures are available as the structure of the vibration plate, and there are, for example, a structure including an elastic film containing silicon as a constituent element and an insulating film containing zirconium as a constituent element. For example, the vibration plate is formed by a material made of silicon oxide (SiO ₂ ) A first vibration layer (elastic film) formed and a first vibration layer (elastic film) formed of zirconia (ZrO ₂ ) The second vibration layer (insulating film) is formed by lamination (see patent document 1).

In addition, in this patent document 1, a structure in which the second portion of the second vibration layer is removed, that is, a structure in which the first vibration layer is left at the wrist portion of the vibration plate and the second vibration layer is removed is disclosed. In this way, by removing the second vibration layer at the wrist portion of the vibration plate, the displacement amount of the vibration plate can be increased while maintaining the strength of the vibration plate.

However, in the case of the structure in which the elastic film is left at the arm portion of the vibration plate and the insulating film is removed as described above, for example, the following problem may occur.

When the insulating film is completely removed from the arm portion of the vibration plate, the insulating film may be removed to a part of the elastic film by overetching, and the reliability of the vibration plate may be lowered. On the other hand, in the case where the insulating film is not completely removed and remains at a predetermined thickness, although a decrease in the reliability of the vibration plate can be suppressed, a sufficient displacement amount of the vibration plate cannot be obtained, and there is a possibility that the vibration efficiency is lowered. As described above, the structure of the vibration plate at the wrist portion has various problems from the viewpoints of reliability, vibration efficiency, and the like.

The problem is not limited to liquid ejecting heads typified by ink jet recording heads that eject ink, and the same applies to other piezoelectric devices.

Patent document 1: japanese patent laid-open No. 2008-78407

Disclosure of Invention

One aspect of the present invention for solving the above problems is a liquid ejecting head comprising: a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode laminated in a first direction; a vibration plate that vibrates by driving the piezoelectric element; a pressure chamber substrate that defines a pressure chamber for applying pressure to a liquid by vibration of the vibration plate, the pressure chamber substrate, the vibration plate, and the piezoelectric element being sequentially laminated in the first direction, the vibration plate including: a first layer containing silicon as a constituent element; a second layer which is arranged between the first layer and the piezoelectric layer and contains a metal element other than zirconium as a constituent element; and a third layer that is disposed between the second layer and the piezoelectric layer and contains zirconium as a constituent element, wherein when a region of the vibration plate that overlaps the pressure chamber when viewed in the first direction and overlaps the first electrode, the piezoelectric layer, and the second electrode is an active region, and when a region of the vibration plate that overlaps the pressure chamber when viewed in the first direction and does not overlap the first electrode, the piezoelectric layer, and the second electrode is a passive region, the vibration plate has the first layer, the second layer, and the third layer in the active region, and has the first layer and the second layer, and does not have the third layer in at least a part of the passive region.

Another aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting head of the above aspect.

Another aspect of the present invention is a piezoelectric device, comprising: a substrate having a concave portion; a piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode laminated in a first direction; a vibration plate that vibrates by driving the piezoelectric element, the substrate, the vibration plate, and the piezoelectric element being sequentially laminated in the first direction, the vibration plate including: a first layer containing silicon as a constituent element; a second layer which is arranged between the first layer and the piezoelectric layer and contains a metal element other than zirconium as a constituent element; and a third layer that is disposed between the second layer and the piezoelectric layer and contains zirconium as a constituent element, wherein when a region of the vibration plate that overlaps the concave portion when viewed in the first direction and overlaps the first electrode, the piezoelectric layer, and the second electrode is set as an active region, and when a region of the vibration plate that overlaps the concave portion when viewed in the first direction and does not overlap the first electrode, the piezoelectric layer, and the second electrode is set as a passive region, the vibration plate has the first layer, the second layer, and the third layer in the active region, and has the first layer and the second layer, and does not have the third layer in at least a part of the passive region.

Drawings

Fig. 1 is a schematic diagram of an inkjet recording apparatus according to embodiment 1.

Fig. 2 is an exploded perspective view of the recording head according to embodiment 1.

Fig. 3 is a plan view of the recording head according to embodiment 1.

Fig. 4 is a cross-sectional view of the recording head according to embodiment 1.

Fig. 5 is a cross-sectional view of the recording head according to embodiment 1.

Fig. 6 is a cross-sectional view of the recording head according to embodiment 2.

Fig. 7 is a cross-sectional view of a recording head according to embodiment 3.

Detailed Description

The present invention will be described in detail based on embodiments. However, the following description is an explanation of one embodiment of the present invention, and the configuration of the present invention can be arbitrarily changed within the scope of the present invention.

Further, X, Y, Z in the respective drawings represents three spatial axes orthogonal to each other. In the present specification, directions along these axes are referred to as an X direction, a Y direction, and a Z direction. The direction in which the arrow mark of each drawing is directed is referred to as the positive (+) direction, and the opposite direction of the arrow mark is referred to as the negative (-) direction. The Z direction indicates a vertical direction, the +z direction indicates a vertical downward direction, and the-Z direction indicates a vertical upward direction. The three spatial axes X, Y, Z, which do not define the positive and negative directions, are described as the X-axis, the Y-axis, and the Z-axis.

Embodiment 1

Fig. 1 is a schematic diagram of an ink jet recording apparatus 1 according to embodiment 1 of the present invention.

First, the overall configuration of the inkjet recording apparatus 1 according to the present embodiment will be described.

An inkjet recording apparatus (hereinafter simply referred to as "recording apparatus") 1 shown in fig. 1 is an example of a liquid ejecting apparatus, and is a printing apparatus that ejects ink, which is one kind of liquid, as ink droplets onto a medium S such as a printing sheet, and performs printing of an image or the like by arranging dots formed on the medium S. In addition to recording paper, any material such as a resin film or cloth may be used as the medium S.

As shown in fig. 1, the recording apparatus 1 includes an inkjet recording head (hereinafter, also simply referred to as a "recording head") 2, a liquid container 3, a control unit 4 as a control unit, a conveying mechanism 5 that sends out a medium S, and a moving mechanism 6.

The recording head 2 is described in detail below, and the recording head 2 ejects ink supplied from the liquid tank 3 from a plurality of nozzles toward the medium S.

The liquid container 3 individually stores a plurality of types (for example, a plurality of colors) of ink ejected from the recording head 2. Examples of the liquid container 3 include a cartridge that can be attached to and detached from the recording apparatus 1, a bag-like ink bag formed of a flexible film, and an ink tank that can be filled with ink. In the liquid container 3, a plurality of different types of ink, for example, different colors, components, and the like are stored.

The control unit 4 includes a control device such as a CPU (Central Processing Unit: central processing unit) or an FPGA (Field Programmable Gate Array: field programmable gate array), and a storage device such as a semiconductor memory. The control unit 4 causes the control device to execute a program stored in the storage device, thereby comprehensively controlling the elements of the recording device 1, that is, the recording head 2, the transport mechanism 5, the moving mechanism 6, and the like.

The conveying mechanism 5 is a mechanism that conveys the medium S in the X-axis direction, and has a conveying roller 7. That is, the conveying mechanism 5 conveys the medium S in the X-axis direction by rotating the conveying roller 7. The transport mechanism 5 for transporting the medium S is not limited to the one provided with the transport roller 7, and may be a mechanism for transporting the medium S by a belt or a drum, for example.

The moving mechanism 6 is a mechanism for reciprocating the recording head 2 in the Y-axis direction, and includes a conveyance body 8 and a conveyance belt 9. The transport body 8 is a substantially box-shaped structure for housing the recording head 2, and is fixed to the transport belt 9. The conveyor belt 9 is an endless belt that is stretched along the Y axis. The recording head 2 reciprocates in the Y-axis direction together with the conveyance body 8 by rotating the conveyance belt 9 under control performed by the control unit 4. The transport body 8 may be configured to mount the liquid container 3 together with the recording head 2.

The recording head 2 performs a jetting operation of jetting ink supplied from the liquid tank 3 from a plurality of nozzles in the +z direction as ink droplets to the medium S under the control of the control unit 4. The ejection operation by the recording head 2 is performed in parallel with the conveyance of the medium S by the conveyance mechanism 5 and the reciprocating movement of the recording head 2 by the movement mechanism 6, so-called printing in which an image composed of ink is formed on the surface of the medium S is performed.

Fig. 2 is an exploded perspective view of the recording head according to the present embodiment, and fig. 3 is a plan view of the recording head, and is a diagram illustrating a schematic configuration of a piezoelectric element. Fig. 4 is a sectional view of the recording head, and is a view corresponding to the line A-A of fig. 3. Fig. 5 is a cross-sectional view illustrating the structure of the diaphragm and the piezoelectric element, and is a view corresponding to line B-B in fig. 3.

As shown in the drawing, the recording head 2 according to the present embodiment includes a pressure chamber substrate 10. The pressure chamber substrate 10 is composed of, for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, or the like.

On the pressure chamber substrate 10, pressure chambers 12 as recesses are arranged in the X-axis direction. The plurality of pressure chambers 12 are arranged on a straight line along the X-axis direction so that the positions in the Y-axis direction become the same. The pressure chambers 12 adjacent to each other in the X-axis direction are partitioned by partition walls 11. Of course, the configuration of the pressure chamber 12 is not particularly limited. For example, the plurality of pressure chambers 12 arranged in parallel in the X-axis direction may be arranged so as to be staggered at positions shifted in the Y-axis direction every other pressure chamber 12.

The pressure chamber 12 of the present embodiment is formed in, for example, a rectangular shape having a length in the Y-axis direction longer than a length in the X-axis direction in a plan view in the +z direction. Of course, the shape of the pressure chamber 12 in a plan view in the +z direction is not particularly limited, and may be a parallelogram shape, a polygonal shape, a circular shape, an oblong shape, or the like. The oblong shape referred to herein is a shape based on a rectangular shape and having both ends in the longitudinal direction in a semicircular shape, and includes a rounded rectangular shape, an elliptical shape, an egg shape, and the like.

On the +z direction side of the pressure chamber substrate 10, a communication plate 15, a nozzle plate 20, and a plastic substrate 45 are laminated in this order.

The communication plate 15 is provided with a nozzle communication passage 16 that communicates the pressure chamber 12 with the nozzle 21. The communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 that form part of the manifold 100, and the manifold 100 serves as a common liquid chamber in which the plurality of pressure chambers 12 communicate with each other. The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the Z-axis direction. The second manifold portion 18 is provided so as to open on the +z-direction side surface without penetrating the communication plate 15 in the Z-axis direction.

The communication plate 15 is provided with a supply communication passage 19 that communicates with one end portion of the pressure chamber 12 in the Y-axis direction, independently of the pressure chamber 12. The supply communication passage 19 communicates the second manifold portion 18 with each pressure chamber 12, and supplies ink in the manifold 100 to each pressure chamber 12.

As the communication board 15, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate, or the like can be used.

The nozzle plate 20 is provided on a surface of the communication plate 15 on the opposite side of the pressure chamber substrate 10, i.e., on the +z direction side. The nozzle plate 20 is formed with nozzles 21 that communicate with the pressure chambers 12 via the nozzle communication passages 16.

In the present embodiment, the plurality of nozzles 21 are provided corresponding to the pressure chambers 12 and are arranged in a row along the X-axis direction. In the nozzle plate 20, the plurality of nozzles 21 are arranged in two rows in the Y-axis direction. That is, the plurality of nozzles 21 in each row are arranged so that the positions in the Y-axis direction become the same position. In addition, the configuration of the nozzle 21 is not particularly limited. For example, the nozzles 21 arranged side by side in the X-axis direction may be arranged at positions shifted in the Y-axis direction every other.

The material of the nozzle plate 20 is not particularly limited, and for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, and a metal substrate can be used. The metal plate may be, for example, a stainless steel substrate. As a material of the nozzle plate 20, an organic material such as polyimide resin may be used.

The plastic substrate 45 is provided on the surface of the communication plate 15 on the opposite side of the pressure chamber substrate 10, that is, on the +z direction side, together with the nozzle plate 20. The plastic substrate 45 is provided around the nozzle plate 20, and seals the openings of the first manifold portion 17 and the second manifold portion 18 provided in the communication plate 15. In the present embodiment, the plastic substrate 45 includes a sealing film 46 made of a flexible thin film, and a fixed substrate 47 made of a hard material such as metal. The region of the fixed substrate 47 facing the manifold 100 becomes the opening 48 which is completely removed in the thickness direction. Therefore, one surface of the manifold 100 is a plastic portion 49 sealed only by the flexible sealing film 46.

On the other hand, a diaphragm 50 and a piezoelectric element 300 for deforming the diaphragm 50 to change the pressure of ink in the pressure chamber 12 are provided on a surface of the pressure chamber substrate 10 opposite to the nozzle plate 20 and the like, that is, on the-Z direction side, and the details thereof will be described below.

A protective substrate 30 having substantially the same size as the pressure chamber substrate 10 is further bonded to the-Z direction side surface of the pressure chamber substrate 10. The protective substrate 30 has a holding portion 31 as a space for protecting the piezoelectric element 300. The holding portion 31 is a member provided for each row of the piezoelectric elements 300 arranged side by side in the X-axis direction, and two holding portions are formed side by side in the Y-axis direction. Further, a through hole 32 penetrating in the Z-axis direction is provided between two holding portions 31 arranged side by side in the Y-axis direction in the protective substrate 30.

Further, a housing member 40 is fixed to the protective substrate 30, and the housing member 40 and the communication plate 15 are partitioned together to form a manifold 100 communicating with the plurality of pressure chambers 12. The case member 40 has substantially the same shape as the communication plate 15 described above in plan view, and is joined to the protection substrate 30 and also joined to the communication plate 15 described above.

The case member 40 has a housing portion 41 on the protective substrate 30 side, and the housing portion 41 is a space having a depth capable of housing the pressure chamber substrate 10 and the protective substrate 30. The housing 41 has an opening area larger than the surface of the protective substrate 30 to which the pressure chamber substrate 10 is bonded. The opening surface of the housing 41 on the nozzle plate 20 side is sealed by the communication plate 15 in a state where the pressure chamber substrate 10 and the protection substrate 30 are housed in the housing 41.

Further, in the case member 40, third manifold portions 42 are respectively formed at both outer sides of the housing portion 41 in the Y-axis direction. The manifold 100 is constituted by the first manifold portion 17, the second manifold portion 18, and the third manifold portion 42 provided in the communication plate 15. The manifold 100 is provided continuously in the X-axis direction, and the supply communication passages 19 that communicate the pressure chambers 12 with the manifold 100 are arranged side by side in the X-axis direction.

The case member 40 is provided with an inlet 44, and the inlet 44 is adapted to communicate with the manifolds 100 and supply ink to each manifold 100. The case member 40 is provided with a connection port 43, and the connection port 43 communicates with the through-hole 32 of the protection board 30 and allows the wiring board 120 to be inserted therethrough.

In the recording head 2 of this embodiment, ink is introduced from the inlet 44 connected to an external ink supply unit, not shown, and after the inside of the manifold 100 to the nozzles 21 is filled with ink, a voltage is applied to each piezoelectric element 300 corresponding to the pressure chamber 12 in accordance with a recording signal from the drive circuit 121. As a result, the diaphragm 50 flexes and deforms together with the piezoelectric element 300, and the pressure in each pressure chamber 12 increases, so that ink droplets are ejected from each nozzle 21.

The structure of the diaphragm 50 and the piezoelectric element 300 according to the present embodiment will be described below. As described above, the diaphragm 50 and the piezoelectric element 300 are provided on the surface of the pressure chamber substrate 10 on the-Z direction side. That is, the pressure chamber substrate 10, the diaphragm 50, and the piezoelectric element 300 are sequentially stacked in the Z-axis direction, which is the first direction.

The piezoelectric element 300 is a pressure generating means, also called a piezoelectric actuator, for generating a pressure change in the ink in the pressure chamber 12. The piezoelectric element 300 includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80, which are stacked in this order from the +z direction side, which is the vibration plate 50 side, toward the-Z direction side.

The portion of the piezoelectric element 300 where piezoelectric strain is generated in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In contrast, a portion of the piezoelectric layer 70 where no piezoelectric strain is generated is referred to as an inactive portion. That is, in the piezoelectric element 300, the portion of the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80 serves as the active portion 310, and the portion of the piezoelectric layer 70 not sandwiched between the first electrode 60 and the second electrode 80 serves as the inactive portion.

In general, one of the first electrode 60 and the second electrode 80 is a separate electrode independent of each active portion 310, and the other is a common electrode common to a plurality of active portions 310. In the present embodiment, the first electrode 60 constitutes an individual electrode, and the second electrode 80 constitutes a common electrode.

Specifically, the first electrode 60 constitutes an individual electrode that is divided for each pressure chamber 12 and is independent for each active portion 310. The first electrode 60 is formed with a width narrower than the width of the pressure chamber 12 in the X-axis direction. That is, the end of the first electrode 60 is located at a position inside the region opposing the pressure chamber 12 in the X-axis direction.

In the Y-axis direction, the end portion of the first electrode 60 on the nozzle 21 side is disposed outside the pressure chamber 12 from the region facing the pressure chamber 12. On the other hand, an end portion of the first electrode 60 on the opposite side from the nozzle 21 is disposed in a region facing the pressure chamber 12.

The material of the first electrode 60 is not particularly limited, and a material having conductivity, for example, iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), chromium (Cr), nickel chromium (NiCr), tungsten (W), titanium (Ti), titanium oxide (TiO _X ) Titanium Tungsten (TiW), and the like.

The piezoelectric layer 70 has a predetermined length in the Y-axis direction and is continuously provided along the X-axis direction. That is, the piezoelectric layers 70 are continuously provided at a predetermined thickness along the parallel arrangement direction of the pressure chambers 12. The thickness of the piezoelectric layer 70 is not particularly limited, and is formed to a thickness of about 1 to 4 μm. Further, the length of the piezoelectric layer 70 in the Y-axis direction is longer than the length of the pressure chamber 12 in the long side direction, that is, in the Y-axis direction, and the piezoelectric layer 70 extends to both outer sides of the pressure chamber 12 in the Y-axis direction.

In the present embodiment, the end portion of the piezoelectric layer 70 on the opposite side from the nozzle 21 is located outside the end portion of the first electrode 60. That is, the end of the first electrode 60 on the opposite side to the nozzle 21 is covered with the piezoelectric layer 70. The end of the piezoelectric layer 70 on the nozzle 21 side is located further inside than the end of the first electrode 60, and the end of the first electrode 60 on the nozzle 21 side is exposed without being covered with the piezoelectric layer 70.

Further, grooves 71 are formed in the piezoelectric layer 70 at positions corresponding to the respective barrier ribs 11. The groove 71 is provided so as to penetrate the piezoelectric layer 70 in the Z-axis direction, which is the thickness direction. However, the groove 71 may be provided to the middle of the piezoelectric layer 70 in the thickness direction, instead of penetrating the piezoelectric layer 70 in the Z-axis direction. That is, a part of the piezoelectric layer 70 may remain on the bottom surface of the groove 71.

The width of the groove 71 in the X-axis direction is the same as the width of the partition wall 11 or wider than the width of the partition wall 11. In the present embodiment, the width of the groove 71 in the X-axis direction is wider than the width of the partition wall 11. Therefore, the end of the piezoelectric layer 70 in the X-axis direction defined by the groove 71 is located at the inner side of the pressure chamber 12. This suppresses rigidity of the portion of the diaphragm 50 facing the opposite ends of the pressure chamber 12 in the X-axis direction, i.e., the arm portion of the diaphragm 50, and therefore facilitates displacement of the piezoelectric element 300.

In addition, the end of the first electrode 60 in the X-axis direction is covered with the piezoelectric layer 70. That is, the end of the piezoelectric layer 70 in the X-axis direction defined by the groove 71 is located inside the pressure chamber 12 and outside the end of the first electrode 60.

Such a piezoelectric layer 70 is formed by a general formula ABO ₃ The piezoelectric material is composed of a composite oxide having a perovskite structure. In the present embodiment, lead zirconate titanate (PZT; pb (Zr, ti) O) is used as the piezoelectric material ₃ ). By using PZT for the piezoelectric material, the piezoelectric layer 70 having a large piezoelectric constant d31 can be obtained.

In the general formula ABO ₃ In the complex oxide having the perovskite structure shown, 12 oxygen ligands are coordinated at the a site and 6 oxygen ligands are coordinated at the B site, thereby forming an octahedron (octahedron). In the present embodiment, in the case of the present embodiment,lead (Pb) is located at the A site, zirconium (Zr) and titanium (Ti) is located at the B site.

The piezoelectric material is not limited to PZT described above. Other elements may be contained in the a site and the B site. For example, the piezoelectric material may be barium zirconate titanate (Ba (Zr, ti) O) ₃ ) Lead lanthanum zirconate titanate ((Pb, la) (Zr, ti) O ₃ ) Lead magnesium niobate zirconate titanate (Pb (Zr, ti) (Mg, nb) O ₃ ) Lead zirconate titanate (Pb (Zr, ti, nb) O) containing silicon ₃ ) And perovskite materials.

The piezoelectric material may be a material in which the content of Pb is suppressed, a so-called low-lead material, or a material in which Pb is not used, a so-called non-lead material. When a low-lead material is used as the piezoelectric material, the amount of Pb used can be reduced. In addition, pb may not be used if a non-lead material is used as the piezoelectric material. Therefore, the use of a low-lead material or a non-lead material as the piezoelectric material can reduce the environmental load. Examples of the non-lead piezoelectric material include bismuth ferrite (BFO; biFeO) ₃ ) BFO-based material of (2) comprising potassium sodium niobate (KNN; KNaNbO ₃ ) KNN-based material of (2).

The second electrode 80 is provided continuously on the side of the piezoelectric layer 70 opposite to the first electrode 60, i.e., on the-Z direction side, and constitutes a common electrode common to the plurality of active portions 310. The second electrode 80 has a length in the Y-axis direction of a predetermined length and is continuously provided along the X-axis direction. The second electrode 80 is also provided on the inner surface of the groove 71, that is, on the side surface of the groove 71 of the piezoelectric layer 70 and on the bottom surface of the groove 71, that is, on the vibration plate 50. Of course, the second electrode 80 may be provided only on a part of the inner surface of the groove 71, or may be provided so as not to extend over the entire inner surface of the groove 71.

The material of the second electrode 80 is not particularly limited, and a noble metal material such as iridium (Ir), platinum (Pt), palladium (Pd), gold (Au), or a conductive oxide typified by Lanthanum Nickel Oxide (LNO) may be used. In this case, the material of the second electrode 80 is preferably a material containing iridium (Ir) and titanium (Ti).

Further, a single lead electrode 91 as a lead-out wiring is led out from the first electrode 60, and a common lead electrode 92 as a lead-out wiring is led out from the second electrode 80. A flexible wiring board 120 is connected to the individual lead electrodes 91 and the common lead electrode 92 at an end portion on the opposite side to the piezoelectric element 300. In the present embodiment, the individual lead electrodes 91 and the common lead electrode 92 are extended so as to be exposed in the through-hole 32 formed in the protective substrate 30, and are electrically connected to the wiring substrate 120 in the through-hole 32. A driving circuit 121 having a switching element for driving the piezoelectric element 300 is mounted on the wiring board 120.

As shown in fig. 5 and the like, the vibration plate 50 includes a first layer 51, a second layer 52, and a third layer 53, and these layers are laminated in this order in the-Z direction. That is, the first layer 51 is a layer of the diaphragm 50 that is disposed on the +z direction side and is in contact with the pressure chamber substrate 10, the third layer 53 is a layer of the diaphragm 50 that is disposed on the-Z direction side and is in contact with the piezoelectric element 300, and the second layer 52 is a layer that is disposed between the first layer 51 and the third layer 53.

Although the interface between the layers constituting the diaphragm 50 is explicitly shown in fig. 5 and the like, the interface may be ambiguous, for example, the structural materials of the two layers may be mixed with each other in the vicinity of the interface between the two layers adjacent to each other.

The first layer 51 is provided on the entire surface of the pressure chamber substrate 10, and contains silicon (Si) as a constituent element. Specifically, the first layer 51 is made of silicon oxide (SiO ₂ ) An elastic film is formed. The method of forming the first layer 51 is not particularly limited, and the first layer 51 is formed by, for example, thermally oxidizing the surface of the pressure chamber substrate 10. The silicon in the first layer 51 may be present in the form of a single body, nitride, oxynitride, or the like, in addition to the oxide.

The third layer 53 is described in detail below, is not provided on the entire surface of the pressure chamber substrate 10, but is provided in a predetermined region, and contains zirconium (Zr) as a constituent element. Specifically, the third layer 53 is, for exampleIs made of zirconia (ZrO ₂ ) An insulating film is formed. The method for forming the third layer 53 is not particularly limited, and the third layer 53 is formed by, for example, thermally oxidizing a layer of zirconium monomer after the layer is formed by sputtering or the like. The zirconium in the third layer 53 may be present in the form of a single body, a nitride, an oxynitride, or the like, in addition to the oxide.

Zirconia has excellent electrical insulation, mechanical strength, and toughness. Therefore, the third layer 53 contains zirconia, whereby the characteristics of the diaphragm 50 can be improved. Further, for example, in the case where the piezoelectric layer 70 is made of lead zirconate titanate, the third layer 53 includes zirconia, and thus there is an advantage that the piezoelectric layer 70 preferentially oriented on the (100) plane with a high orientation ratio can be easily obtained when the piezoelectric layer 70 is formed.

The second layer 52 is a layer including an element other than zirconium as a constituent element, and is provided between the first layer 51 and the third layer 53, and is provided on the entire surface of the pressure chamber substrate 10. Since contact of the first layer 51 and the third layer 53 is prevented by the second layer 52, the reduction of the silicon oxide in the first layer 51 by zirconium in the third layer 53 can be reduced.

Here, the second layer 52 is preferably a layer containing a metal element which is less oxidized than zirconium which is a constituent element of the third layer 53, and more preferably is composed of an oxide of the metal element. In other words, the second layer 52 preferably contains a metal element having an oxide formation free energy larger than that of zirconium. The magnitude relation of the free energy of oxide formation can be evaluated based on a known free energy diagram (Ellingham diagram) of oxide, for example.

Specifically, the second layer 52 is preferably configured to contain, as a constituent element, any metal element selected from titanium (Ti), aluminum (Al), chromium (Cr), and tantalum (Ta). The second layer 52 may contain only one metal element, or may contain two or more metal elements.

By including the metal element which is less oxidized than zirconium in the second layer 52, reduction of the silicon oxide included in the first layer 51 can be reduced as compared with the case where the second layer 52 includes a metal element which is more oxidized than zirconium, that is, as compared with the structure in which the free energy of oxide formation of the metal element included in the second layer 52 is smaller than the free energy of oxide formation of zirconium. As a result, the adhesion force between the first layer 51 and the third layer 53 can be improved as compared with a structure in which the second layer 52 is not used.

Further, by providing the second layer 52, formation of a gap at the interface of the third layer 53 can be suppressed. That is, entry of moisture into the interface between the third layer 53 and the second layer 52 can be suppressed. Therefore, embrittlement of the zirconium of the third layer 53 due to moisture can be suppressed, and breakage such as peeling and cracking of the third layer 53 can be suppressed.

Further, it is preferable that the Young's modulus of the material of the second layer 52 is higher than that of the material of the first layer 51. As described above, the second layer 52 preferably contains any one of titanium (Ti), aluminum (Al), chromium (Cr), and tantalum (Ta) as a constituent element. This can suppress overetching when etching the third layer 53 as will be described later.

It is further preferable that the Young's modulus of the material of the second layer 52 is higher than that of the material of the third layer 53. For example, young's modulus of titanium (Ti) or aluminum (Al) is higher than young's modulus of zirconium (Zr) as a material of the third layer 53. Therefore, by using the above-described material for the second layer 52, the function as an etching stopper can be ensured even if the thickness of the second layer 52 is made relatively thin. Further, by making the thickness of the second layer 52 thin, the displacement of the vibration plate 50 can also be improved. In addition, by using the second layer 52, atomic diffusion is suppressed using these materials. As a result, the occurrence of leakage current can be suppressed.

On the other hand, for example, chromium (Cr) and tantalum (Ta) have lower young's modulus than zirconium (Zr) which is a material of the third layer 53. Therefore, by using these materials as the material of the second layer 52, the displacement amount of the vibration plate 50 is easily increased. Even when these materials are used, the second layer 52 can function as an etching stop layer by increasing the thickness thereof.

In the recording head 2 according to the present invention, the third layer 53 constituting the diaphragm 50 is not provided on the entire surface of the diaphragm 50, but is provided in a predetermined region.

Specifically, as shown in fig. 5, the third layer 53 is provided in the region corresponding to each pressure chamber 12 in the X-axis direction, which is the direction orthogonal to the extraction direction of the individual lead electrode 91. In the present embodiment, the third layer 53 is formed to have substantially the same width as the piezoelectric layer 70. That is, both ends of the third layer 53 in the X-axis direction are located inside the pressure chamber 12 and outside the end of the first electrode 60. Therefore, a portion where the third layer 53 is not formed exists at a portion facing both ends of the pressure chamber 12 in the X-axis direction, i.e., a portion of the arm portion of the so-called diaphragm 50. This can increase the displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300. In addition, the positions of both end portions of the third layer 53 in the Y-axis direction are located at the outer sides of the pressure chamber 12, respectively, in the present embodiment.

In this way, the third layers 53 are provided in the X-axis direction in the areas corresponding to the respective pressure chambers 12, respectively, in a separated manner. In other words, the diaphragm 50 has the following structure. For example, in fig. 5, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction, which is the first direction, and overlaps the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as an active region A1. That is, a region of the diaphragm 50 facing the pressure chamber 12 that overlaps the active portion 310 of the piezoelectric element 300 is referred to as an active region A1.

In addition, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction and that does not overlap the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as a passive region A2. That is, a region of the diaphragm 50 facing the pressure chamber 12, which does not overlap with the active portion 310 of the piezoelectric element 300, is referred to as a passive region A2. In the present embodiment, the region overlapping the pressure chamber 12 and not overlapping the first electrode 60 when viewed in the Z-axis direction is the inactive region A2. That is, a region of the diaphragm 50 opposed to the pressure chamber 12, which is different from the active region A1, is the inactive region A2. The inactive area A2 includes an area corresponding to the wrist portion of the so-called vibrating plate 50, and in the present embodiment, the active area A1 is located between two inactive areas A2 when viewed in cross section in the Z-axis direction.

In the present embodiment, the pressure chamber substrate 10, the diaphragm 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are stacked in this order in the Z-axis direction, and the second electrode 80 as a common electrode is continuously provided from the active region A1 to the inactive region A2.

Further, in the X-axis direction, the vibration plate 50 of the active region A1 has a first layer 51, a second layer 52, and a third layer 53. On the other hand, in the X-axis direction, the vibration plate 50 of a part of the inactive area A2 has the first layer 51 and the second layer 52, but does not have the third layer 53. That is, although the first layer 51 and the second layer 52 constituting the diaphragm 50 are formed so as to continuously span the entire area between the active area A1 and the inactive area A2, the third layer 53 is removed in a part of the inactive area A2. In the present embodiment, the third layer 53 is removed in a region of a part of the inactive region A2 on the partition wall 11 side. As described above, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction, which is the first direction, and that does not overlap the third layer 53 is referred to as a removal region A3. The removal region A3 is a part of the inactive region A2. The vibration plate 50 in the removed area A3 is constituted by a first layer 51 and a second layer 52. In the present embodiment, the position of the end portion of the third layer 53 in the X-axis direction, that is, the boundary of the removed area A3 is located on the extension line of the end face of the piezoelectric layer 70 defined by the groove 71.

In the present embodiment, the third layer 53 is removed not only in the inactive region A2 but also in the region outside the pressure chamber 12 in the X-axis direction. That is, in the X-axis direction, at the region outside the pressure chamber 12, the vibration plate 50 is also constituted by the first layer 51 and the second layer 52. However, the third layer 53 in the region outside the pressure chamber 12 may not be removed.

As described above, the recording head 2 according to the present embodiment includes: a piezoelectric element 300 including a first electrode 60, a piezoelectric layer 70, and a second electrode 80 laminated in a first direction, i.e., a Z-axis direction; a vibration plate 50 that vibrates by driving of the piezoelectric element 300; a pressure chamber substrate 10 that defines a pressure chamber 12 for applying pressure to ink as a liquid by vibration of a diaphragm 50, the pressure chamber substrate 10, the diaphragm 50, and the piezoelectric element 300 being laminated in this order in the Z-axis direction, the diaphragm 50 including: a first layer 51 containing silicon as a constituent element; a second layer 52 that is disposed between the first layer 51 and the first electrode 60 and that contains a metal element other than zirconium as a constituent element; a third layer 53 that is disposed between the second layer 52 and the first electrode 60 and contains zirconium as a constituent element, wherein when the region of the diaphragm 50 that overlaps the pressure chamber 12 and overlaps the first electrode 60, the piezoelectric layer 70, and the second electrode 80 when viewed in the Z-axis direction is set as an active region A1, and when the region of the diaphragm 50 that overlaps the pressure chamber 12 and does not overlap the first electrode 60, the piezoelectric layer 70, and the second electrode 80 when viewed in the Z-axis direction is set as a passive region A2, the diaphragm 50 has the first layer 51, the second layer 52, and the third layer 53 at the active region A1, and has the first layer 51 and the second layer 52 at least a portion of the passive region A2, and does not have the third layer 53.

With such a configuration, the displacement amount of the diaphragm 50 accompanying the driving of the piezoelectric element 300 can be increased, and the occurrence of cracks in the diaphragm 50 can be suppressed. Further, by providing the second layer 52 to the diaphragm 50 in the active region A1 and the inactive region A2, when the third layer 53 is removed by, for example, dry etching in a portion of the inactive region A2, that is, in the wrist portion of the diaphragm, the first layer 51 including silicon as a constituent element is not removed by overetching. Therefore, the reliability of the vibration plate 50 can be prevented from being lowered.

Here, at least a part of the inactive region A2 of the diaphragm 50, in the present embodiment, the third layer 53 including zirconium as a constituent element is removed in the removal region A3, and thus an end portion of the third layer 53 may be present in the inactive region A2. Therefore, moisture may enter from the end portion of the third layer 53 to the interface between the third layer 53 and the underlying layer, and peeling, cracking, and other damage of the third layer 53 may occur.

However, in the present invention, the adhesion of the third layer 53 is improved by providing the diaphragm 50 with the second layer 52 containing a metal element other than zirconium as a constituent element, that is, providing the second layer 52 as a base layer of the third layer 53. Therefore, entry of moisture from the end portion of the third layer 53 existing in the inactive area A2 to the interface between the third layer 53 and the second layer 52 can be suppressed. Therefore, embrittlement of the zirconium of the third layer 53 due to moisture can be suppressed, and breakage such as peeling and cracking of the third layer 53 can be suppressed.

In addition, in the removed region A3 of the diaphragm 50 in which the third layer 53 is removed in the inactive region A2, the thickness of the diaphragm 50 is reduced and stress is easily concentrated, so that there is a possibility that cracks or peeling of the second electrode 80 provided in the removed region A3 may occur.

However, in the present invention, the second electrode 80 is directly laminated on the second layer 52 in the removed area A3 of the diaphragm 50, and the second electrode 80 and the second layer 52 are formed of materials having high affinity to each other. For example, when a metal material such as titanium (Ti) or iridium (Ir) is used as the material of the second layer 52, an oxide or nitride of the metal material is used as the material of the second layer 52. That is, the second electrode 80 includes a single body of a metal element, and the second layer 52 includes an oxide or nitride of the metal element.

This can improve the adhesion between the second layer 52 of the vibration plate 50 and the second electrode 80 constituting the piezoelectric element 300, and can suppress breakage of the vibration plate 50 and the second electrode 80 at the wrist.

Further, the second layer 52 is preferably formed continuously between the active area A1 and the inactive area A2 of the diaphragm 50. That is, the second layer 52 is preferably formed across all the areas in the active area A1 and the inactive area A2. This makes it easy to suppress the occurrence of cracks in the diaphragm 50.

In addition, the second layer 52 may not necessarily be formed continuously between the active region A1 and the inactive region A2 of the diaphragm 50. For example, a region where the second layer 52 is not formed may be present at a part of the center portion of the region of the diaphragm 50 where the third layer 53 is formed.

Further, it is preferable that the Young's modulus of the material of the second layer 52 is higher than that of the material of the first layer 51. Thus, overetching is easily suppressed when etching the third layer 53 of the diaphragm 50.

Preferably, the second layer 52 contains a metal element that is less oxidized than zirconium, which is a constituent element of the third layer 53, as a constituent element. Preferably, the second layer 52 contains any metal element of titanium, aluminum, chromium, and tantalum as a constituent element.

In the relation between the first layer 51 and the third layer 53, zirconium (Zr) contained in the third layer is relatively easily oxidized, and silicon oxide (SiO) contained in the first layer 51 ₂ ) Is easily reduced. Therefore, when the third layer 53 and the first layer 51 are directly stacked, the silicon oxide of the first layer is reduced. By diffusion of the silicon monomer generated by the reduction from the first layer 51 to the third layer 53, a void may be generated at the interface of the third layer 53.

However, by providing the second layer 52 between the first layer 51 and the third layer 53 and including the second layer 52 containing a metal element which is less likely to be oxidized than zirconium which is a constituent element of the third layer 53, generation of voids due to the diffusion can be suppressed. Therefore, the adhesion force of the third layer 53 can be improved, and breakage such as peeling and cracking of the third layer 53 can be suppressed.

In addition, it is preferable that the second layer 52 of the vibration plate 50 is laminated adjacent to one of the first electrode 60 and the second electrode 80 at least in a part of the inactive area A2. For example, in the present embodiment, the second layer 52 of the vibration plate 50 is laminated adjacent to the second electrode 80 at least at a part of the inactive area A2, that is, at the removal area A3.

Further, it is preferable that the constituent elements of the second electrode 80 stacked adjacent to the second layer 52 of the vibration plate 50 include metal elements included in the second layer 52. Further, the second electrode 80 stacked adjacent to the second layer 52 of the vibration plate 50 preferably includes a single body of the metal element, and the second layer 52 includes an oxide or nitride of the metal element.

The removed area A3 of the inactive area A2, which overlaps the pressure chamber 12 when viewed in the first direction, i.e., the Z-axis direction, and does not include the third layer 53, preferably does not overlap the piezoelectric layer 70 when viewed in the first direction. This is because the crystallinity of the piezoelectric layer 70 is more easily homogenized than in the case where the piezoelectric layer 70 is continuously formed on both the region of the diaphragm 50 where the third layer 53 is formed and the region where the third layer 53 is not formed.

In the present embodiment, the position of the end portion of the third layer 53 of the diaphragm 50 in the X-axis direction is located on the extension line of the end face of the piezoelectric layer 70, but the position of the end portion of the third layer 53 may not necessarily be located on the extension line of the end face of the piezoelectric layer 70. The position of the end of the third layer 53 in the X-axis direction may be outside the extension line of the end surface of the piezoelectric layer 70. The end portion of the third layer 53 in the X-axis direction may be positioned further inward than the extension line of the end surface of the piezoelectric layer 70.

In the present embodiment, the third layer 53 is removed in the removed area A3 which is a part of the inactive area A2, but the range of the removed area A3 in the inactive area A2 is not particularly limited, and it is also possible to match the inactive area A2 and the removed area A3, for example. That is, the third layer 53 may not be formed in the entire inactive area A2.

Embodiment 2

The present embodiment is a modification of the diaphragm 50 and the piezoelectric element 300 provided in the recording head 2, and the configuration is the same as that of embodiment 1 except for this. The same reference numerals are given to the same components as those in embodiment 1, and duplicate descriptions are omitted. The recording head 2 according to the present embodiment is also characterized by the structure of the diaphragm 50, and the basic structure of the piezoelectric element 300 is a conventional structure.

As shown in fig. 6, the recording head 2 according to the present embodiment includes a piezoelectric element 300 provided on the-Z side of the diaphragm 50, and the first electrode 60 of the piezoelectric element 300 forms a common electrode and the second electrode 80 forms a single electrode.

The diaphragm 50 has the first layer 51, the second layer 52, and the third layer 53 as in embodiment 1, and these layers are laminated in this order in the-Z direction, and the third layer 53 is provided not on the entire surface of the diaphragm 50 but in a predetermined region. That is, in the X-axis direction, the third layer 53 is formed narrower than the width of the pressure chamber 12.

The first electrode 60 constituting the piezoelectric element 300 according to the present embodiment is provided continuously across the region corresponding to the plurality of pressure chambers 12 on the diaphragm 50 having the first layer 51, the second layer 52, and the third layer 53, and serves as a common electrode shared by the plurality of active portions 310. That is, the first electrode 60 is continuously formed on the second layer 52 and the third layer 53 of the vibration plate 50 in the X-axis direction.

The second electrode 80 is laminated on the-Z direction side of the first electrode 60 via the piezoelectric layer 70, and constitutes an individual electrode that is divided for each pressure chamber 12 so as to be independent for each active portion 310. The second electrode 80 is formed narrower than the width of the pressure chamber 12 in the X-axis direction. That is, in the X-axis direction, the end portion of the second electrode 80 is located at the inner side of the region opposed to the pressure chamber 12. In the present embodiment, the position of the end portion of the second electrode 80 in the X-axis direction substantially coincides with the position of the end portion of the piezoelectric layer 70.

Further, the piezoelectric element 300 is provided with a protective film 150 made of an insulating material. Although not shown, a common lead electrode connected to the first electrode 60 and an individual lead electrode connected to each of the second electrodes 80 are provided on the protective film 150.

In the recording head 2 of this embodiment, the diaphragm 50 has the following structure as in embodiment 1. For example, in fig. 6, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction, which is the first direction, and overlaps the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as an active region A1. That is, a region of the diaphragm 50 facing the pressure chamber 12 that overlaps the active portion 310 of the piezoelectric element 300 is referred to as an active region A1. In addition, a region of the vibration plate 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction and that does not overlap the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as a passive region A2. That is, a region of the diaphragm 50 facing the pressure chamber 12, which does not overlap with the active portion 310 of the piezoelectric element 300, is referred to as a passive region A2. The inactive area A2 includes an area corresponding to the wrist portion of the so-called vibration plate 50, and in the present embodiment, the active area A1 is located between the two inactive areas A2 when viewed in cross section along the Z-axis direction.

In addition, in the Z-axis direction, the pressure chamber substrate 10, the diaphragm 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated in this order, and the first electrode 60 as a common electrode is continuously provided from the active region A1 to the inactive region A2 in the X-axis direction.

Further, the vibration plate 50 of the active region A1 in the X-axis direction has a first layer 51, a second layer 52, and a third layer 53. On the other hand, the diaphragm 50, which is a part of the inactive area A2 in the X-axis direction, has the first layer 51 and the second layer 52, but does not have the third layer 53. That is, although the first layer 51 and the second layer 52 constituting the vibration plate 50 are formed continuously and globally between the active area A1 and the inactive area A2, the third layer 53 is removed at a portion of the inactive area A2. That is, the third layer 53 is removed in the removal region A3 on the partition wall 11 side of the inactive region A2, and the diaphragm 50 at the removal region A3 is composed of the first layer 51 and the second layer 52.

In the structure of this embodiment, the same operational effects as those of embodiment 1 can be obtained. For example, the occurrence of cracks in the diaphragm 50 can be suppressed while increasing the displacement amount of the diaphragm 50 accompanying the driving of the piezoelectric element 300. Further, by providing the second layer 52 to the diaphragm 50 in the active region A1 and the inactive region A2, overetching at the time of etching the third layer 53 at the arm portion of the diaphragm 50 can be suppressed, and further, a decrease in reliability of the diaphragm 50 can be prevented.

Embodiment 3

Fig. 7 is a cross-sectional view of a recording head according to embodiment 3.

The present embodiment is similar to the above embodiment except that the present embodiment is a modification of the diaphragm 50 and the piezoelectric element 300 provided in the recording head 2. The same reference numerals are given to the same components as those in embodiment 1, and duplicate descriptions are omitted. The recording head 2 according to the present embodiment is also characterized by the structure of the diaphragm 50, and the basic structure of the piezoelectric element 300 is a conventional structure.

As shown in fig. 7, the piezoelectric element 300 is provided on the-Z direction side of the pressure chamber substrate 10 via the diaphragm 50 having the first layer 51, the second layer 52, and the third layer 53, and includes the first electrode 60, the piezoelectric layer 70, and the second electrode 80 laminated in the Z axis direction.

Although not shown, the active portion 310 of the piezoelectric element 300 is provided annularly along the opening edge portion of each pressure chamber 12 in a plan view as viewed along the Z-axis direction, and is not provided at the central portion of the pressure chamber 12.

Accordingly, in the cross section in the X-axis direction shown in fig. 7, the active portions 310 of the piezoelectric element 300 are provided corresponding to both end portions of the pressure chamber 12, and are not provided at the central portion of the pressure chamber 12. In the section in the Y-axis direction, the active portion 310 of the piezoelectric element 300 has the same structure. That is, the active portion 310 extends from the inside of the pressure chamber 12 to the outside of the pressure chamber 12 at whichever position of the opening edge portion of the pressure chamber 12.

The first electrode 60 constituting the piezoelectric element 300 is a common electrode common to the plurality of active portions 310, and is continuously provided on the-Z direction side of the diaphragm 50 so as to span the regions corresponding to the plurality of pressure chambers 12. The piezoelectric layer 70 is provided independently for each pressure chamber 12, that is, for each active portion 310. The piezoelectric layer 70 is provided in a ring shape with a predetermined width along the opening edge portion of the pressure chamber 12, not provided at a portion corresponding to the central portion of the pressure chamber 12. In the present embodiment, the piezoelectric layer 70 is provided independently so as to be divided for each active portion 310, but may be provided continuously across a plurality of active portions 310.

The second electrode 80 is provided on the opposite side of the piezoelectric layer 70 from the first electrode 60, and constitutes an individual electrode independent for each active portion 310. In the present embodiment, the second electrode 80 is provided continuously on the piezoelectric layer 70 constituting each active portion 310. That is, the second electrode 80 is provided in a ring shape along the opening edge portion of the pressure chamber 12 with the same width as the piezoelectric layer 70, and is not provided at a portion corresponding to the central portion of the pressure chamber 12. The portion where the second electrode 80 is provided becomes an active portion 310 of the piezoelectric element 300.

Here, in the recording head 2 according to the present embodiment, the third layer 53 constituting the diaphragm 50 is also provided not on the entire surface of the diaphragm 50 but in a predetermined region.

Specifically, the third layer 53 constituting the diaphragm 50 is provided in a region facing each pressure chamber 12 so as to correspond to the active portion 310. That is, the third layer 53 is provided at a position facing the peripheral edge portion of the pressure chamber 12 in the region facing the pressure chamber 12, but is not provided at a position facing the central portion of the pressure chamber 12.

Therefore, in the cross section in the X-axis direction, which is the direction in which the pressure chambers 12 are arranged side by side, as shown in fig. 7, the third layer 53 is provided at positions corresponding to both end portions of the pressure chambers 12, and is not provided at the central portion of the pressure chambers 12. The position of the end of the third layer 53 in the region opposed to the pressure chamber 12 is located on the extension line of the end face of the piezoelectric layer 70. However, the position of the end portion of the third layer 53 may not necessarily be located on the extension line of the end face of the piezoelectric layer 70, and may be located on the inner side and the outer side of the extension line of the end face of the piezoelectric layer 70 as long as the position is located in the inactive region A2. In the section in the Y axis direction, the diaphragm 50 including the third layer 53 has the same structure.

In the structure of the present embodiment, a portion of the diaphragm 50 corresponding to the central portion of the pressure chamber 12 corresponds to a so-called wrist portion. That is, in the structure of the present embodiment, there is also a portion where the third layer 53 is not formed at the arm portion of the so-called vibration plate 50. This can increase the displacement of the diaphragm 50 associated with the driving of the piezoelectric element 300.

In addition, the third layer 53 is continuously formed in the region outside the pressure chamber 12. Of course, the third layer 53 need not be continuous in the area outside the pressure chamber 12. For example, the third layer 53 may be removed from the region where the piezoelectric layer 70 is not formed outside the pressure chamber 12.

The diaphragm 50 including the third layer 53 is also structured as follows in the present embodiment. For example, in fig. 7, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction, which is the first direction, and overlaps the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as an active region A1. That is, a region of the diaphragm 50 facing the pressure chamber 12 that overlaps the active portion 310 of the piezoelectric element 300 is referred to as an active region A1. In addition, a region of the diaphragm 50 that overlaps the pressure chamber 12 when viewed in the Z-axis direction and that does not overlap the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is referred to as a passive region A2. That is, a region of the diaphragm 50 facing the pressure chamber 12, which does not overlap with the active portion 310 of the piezoelectric element 300, is referred to as a passive region A2. That is, in the present embodiment, a region of the diaphragm 50 facing the pressure chamber 12, which is facing the center portion of the pressure chamber 12, is a non-active region A2, and the non-active region A2 is located between the two active regions A1 when viewed in cross section in the Z-axis direction.

In the present embodiment, the pressure chamber substrate 10, the diaphragm 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are stacked in this order, and the first electrode 60 serving as a common electrode is continuously provided from the active region A1 to the inactive region A2.

Further, the vibration plate 50 of the active region A1 has a first layer 51, a second layer 52, and a third layer 53. On the other hand, the diaphragm 50 of the inactive area A2 has the first layer 51 and the second layer 52, but does not have the third layer 53. That is, the first layer 51 and the second layer 52 constituting the vibration plate 50 are formed continuously and globally between the active area A1 and the inactive area A2, but the third layer 53 is removed at least at a portion of the inactive area A2. That is, the third layer 53 is removed at the removal region A3 of the central portion other than the outer peripheral portion of the inactive region A2, so that the vibration plate 50 at the removal region A3 is constituted by the first layer 51 and the second layer 52.

In the configuration of this embodiment, the same operational effects as those of the above-described embodiment can be obtained. For example, the occurrence of cracks in the diaphragm 50 can be suppressed while increasing the displacement amount of the diaphragm 50 accompanying the driving of the piezoelectric element 300. Further, since the diaphragm 50 has the second layer 52 in the active region A1 and the inactive region A2, overetching can be suppressed when etching the third layer 53 in a portion of the diaphragm 50 corresponding to the center portion of the pressure chamber 12, that is, in the wrist portion of the diaphragm 50, and a decrease in reliability of the diaphragm 50 can be prevented.

Other embodiments

Although the embodiments of the present invention have been described above, the basic configuration of the present invention is not limited to the above configuration.

For example, in the above-described embodiment, the structure including the first layer 51, the second layer 52, and the third layer 53 is illustrated as the diaphragm 50, but the structure of the diaphragm 50 is not limited to this. The diaphragm 50 may be configured to include layers other than the first layer 51, the second layer 52, and the third layer 53. For example, the vibration plate 50 may include a fourth layer as a stress control layer between the first layer 51 and the second layer 52.

In the above-described embodiment, the structure of the diaphragm 50 in the short-side direction of the pressure chamber 12 has been described as an example, but the present invention is of course applicable to the structure of the diaphragm 50 in the long-side direction of the pressure chamber 12.

In the above-described embodiment, the recording head 2 is mounted on the transport body 8 and reciprocates along the Y axis, which is the main scanning direction, as the recording apparatus 1, but the configuration of the recording apparatus 1 is not limited to this. The present invention can be applied to a so-called line type recording apparatus in which the recording head 2 is fixed, and printing is performed by moving a medium S such as paper along an X axis which is a sub-scanning direction, for example.

In the above-described embodiments, the ink jet recording head is exemplified as an example of the liquid ejecting head, and the ink jet recording apparatus is exemplified as an example of the liquid ejecting apparatus, but the present invention is an invention which is intended to be widely used in the liquid ejecting head and the liquid ejecting apparatus as a whole. The present invention can be applied to a liquid ejecting head and a liquid ejecting apparatus that eject a liquid other than ink. Examples of the other liquid ejecting head include various recording heads used in image recording apparatuses such as printers, color material ejecting heads used for manufacturing color filters such as liquid crystal displays, electrode material ejecting heads used for forming electrodes of organic EL (Electro Luminescence: electroluminescence) displays, FED (field emission displays) and the like, and bioorganic material ejecting heads used for manufacturing biochips. The present invention can also be applied to a liquid ejecting apparatus including the liquid ejecting head.

The present invention is not limited to the liquid ejecting head represented by the ink jet recording head, and can be applied to piezoelectric devices such as ultrasonic devices, motors, pressure sensors, thermoelectric elements, and ferroelectric elements. The present invention can be applied to a finished product using these piezoelectric devices, for example, an ultrasonic sensor using the ultrasonic device, a robot using the motor as a driving source, an IR sensor using the thermoelectric element, a ferroelectric memory using the ferroelectric element, and the like, in addition to a liquid ejecting apparatus using the liquid ejecting head.

Symbol description

1 … ink jet recording apparatus (recording apparatus); 2 … recording heads; 3 … liquid container; 4 … control unit; 5 … conveying mechanism; 6 … movement mechanism; 7 … conveyor rolls; 8 … transporter; 9 … conveyor belt; 10 … pressure chamber substrate; 11 … partition walls; 12 … pressure chamber; 15 … communication plates; 16 … nozzle communication channels; 17 … first manifold portion; 18 … second manifold portion; 19 … feed communication channels; 20 … nozzle plate; 21 … nozzle; 30 … protective substrate; 31 … holding portion; 32 … through holes; 40 … housing parts; 41 … storage part; 42 … third manifold portion; 43 … connection port; 44 … inlet; 45 … plastic substrates; 46 … sealing film; 47 … fixed substrate; 48 … opening portions; 49 … plastic part; 50 … vibrating plate; 51 … first layer; 52 … second layer; 53 … third layer; 60 … first electrode; 70 … piezoelectric layers; 71 … groove portions; 80 … second electrode; 91 … individual lead electrodes; 92 … share a lead electrode; a 100 … manifold; 120 … wiring substrate; 121 … drive circuit; 150 … protective film; 300 … piezoelectric element; 310 … active portion; s … medium; a1 … active region; a2 … inactive region; a3 … removed area.

Claims

1. A liquid ejecting head, comprising:

A piezoelectric element including a first electrode, a piezoelectric layer, and a second electrode laminated in a first direction;

a vibration plate that vibrates by driving the piezoelectric element;

a pressure chamber substrate that defines a pressure chamber for applying pressure to the liquid by vibration of the vibration plate,

the pressure chamber substrate, the vibration plate, and the piezoelectric element are laminated in this order in the first direction,

the vibration plate includes:

a first layer containing silicon as a constituent element;

a second layer which is arranged between the first layer and the piezoelectric layer and contains a metal element other than zirconium as a constituent element;

a third layer which is arranged between the second layer and the piezoelectric layer and contains zirconium as a constituent element,

a region of the vibration plate that overlaps the pressure chamber and overlaps the first electrode, the piezoelectric layer, and the second electrode when viewed in the first direction is set as an active region, and

when a region of the vibration plate that overlaps the pressure chamber when viewed in the first direction and that does not overlap the first electrode, the piezoelectric layer, and the second electrode is set as a passive region,

The vibration plate has the first layer, the second layer and the third layer in the active region, and

in at least a portion of the inactive area, the first layer and the second layer are present, and the third layer is absent.

2. The liquid ejecting head according to claim 1, wherein,

the second layer is continuously formed between the active region and the inactive region.

3. The liquid ejecting head according to claim 1, wherein,

the Young's modulus of the material of the second layer is higher than the Young's modulus of the material of the first layer.

4. A liquid ejection head according to any one of claim 1 to 3, wherein,

the second layer contains any metal element of titanium, aluminum, chromium, tantalum as a constituent element.

5. A liquid ejection head according to any one of claim 1 to 3, wherein,

the second layer contains a metal element which is difficult to oxidize compared to zirconium as a constituent element.

6. The liquid ejecting head according to claim 1 or 2, wherein,

in at least a part of the inactive region, the second layer of the vibration plate is laminated adjacent to one of the first electrode and the second electrode.

7. The liquid ejecting head according to claim 6, wherein,

the constituent element of the one electrode stacked adjacent to the second layer of the diaphragm includes the metal element included in the second layer.

8. The liquid ejecting head according to claim 7, wherein,

the one electrode stacked adjacent to the second layer of the vibration plate includes a single body of the metal element,

the second layer contains an oxide or nitride of the metal element.

9. The liquid ejecting head according to claim 1 or 2, wherein,

the region of the inactive region that overlaps the pressure chamber when viewed in the first direction and that does not have the third layer does not overlap the piezoelectric layer when viewed in the first direction.

10. The liquid ejecting head according to claim 1 or 2, wherein,

the active region is located between two of the inactive regions when viewed in cross-section in the first direction.

11. The liquid ejecting head according to claim 10, wherein,

in the first direction, the pressure chamber substrate, the diaphragm, the first electrode, the piezoelectric layer, and the second electrode are laminated in this order,

The second electrode is continuously disposed from the active region to the inactive region.

12. The liquid ejecting head according to claim 10, wherein,

the first electrode is continuously disposed from the active region to the inactive region.

13. The liquid ejecting head according to claim 1 or 2, wherein,

the inactive region is located between two of the active regions when viewed in cross-section in the first direction.

14. A liquid ejecting apparatus is characterized in that,

the liquid ejecting head as claimed in claim 1.

15. A piezoelectric device, comprising:

a substrate having a concave portion;

a vibration plate that vibrates by driving the piezoelectric element,

the substrate, the vibration plate, and the piezoelectric element are laminated in this order in the first direction,

the vibration plate includes:

a first layer containing silicon as a constituent element;

a region of the vibration plate that overlaps the concave portion and overlaps the first electrode, the piezoelectric layer, and the second electrode when viewed in the first direction is set as an active region, and

when a region of the vibration plate that overlaps the concave portion when viewed in the first direction and that does not overlap the first electrode, the piezoelectric layer, and the second electrode is set as a passive region,